In recognizing Kenyan Geoffrey Mutai's mark of 2:03:02 at the 2011 Boston Marathon as (at the time) the fastest Marathon ever run, the IAAF has noted: Due to the elevation drop and point-to-point measurements of the Boston course, performances [on that course] are not eligible for World record consideration..
There are three types of embryonic cells; endoderm, mesoderm, and ectoderm. In the human body there are many different types of cells, more than two. They are grouped into tissue types. We have four different tissues; connective, nervous, muscular, and epithelial. The two major groups of cell types in the human body are somatic cells and gamete cells. There are three types of embryonic cells; endoderm, mesoderm, and ectoderm. In the human body there are many different types of cells, more than two. They are grouped into tissue types. We have four different tissues;  connective, nervous, muscular, and epithelial.
There are two major types of cells: prokaryotic and eukaryotic cells. Ribosomes are cell organelles that consist of RNA and proteins. They are responsible for assembling the proteins of the cell. Depending on the protein production level of a particular cell, ribosomes may number in the millions.